Frequency-relay.



D. J. MQGARTHY.

,FREQUENGY RELAI.

APPLICATION FILED 111 12.24, 1907.

928,53 1 Patented July 20, 1909.

WITNESSES i v:NiENTO I DAN lllli .T. 1llC(,.\RTllY, OF \YlLKIN SlGNAL COMPANY, OF SWISSVALE,

NIA.

PENNSYLVANIA.

FREQUENCY-RELAY.

Specification of Letters Patent.

Patented Jul 20, 1909'.

Application filed April 24, 1907. Serial No. 370,019.

To all 'ZIJ/ lOIIl it may concern:

Be it known that I, DANIEL of il' illiinshurg Allegheny county,

J. MCCARTHY,

Pennsylvania, have invented a new and useful Freqiierd y-lwlay of which the following is a full,

clear, and exact description, reference being had to the accompanying drawing, forming part of this specification, in which the figure is a perspective view showing one form of my invention. 4

My invention relates to the class of designed for use in circuits wherein .tri'vo or more alternating electric currents ofchflierent frequencies are employed. It

is designejthto provide a selective apparatus as between the currents of dilferent will operate on a current of frequency, and be inoperative anotherfrequency.

equencies, so that it predetermined on currents of The invention is based on the principle of resonance; that is, on the balance that may he established between a capacity and a coil having self-induction when ternating current circuit.

aced in an al- If a rcondenser and a coil having self-induction arq'pu't in series in an alternating current circuit, the re-' actance of the condenstr will he opposite to that of the inductance coil, and the relative magnitude of these two react ances may he resistance.

The condition necessary to obtain this halance is indicated by the equation disturb the balance.

: ii p, where (l the capacity of the the induction CUOlllOlPl'll'. depending It can readily be seen value of will balance is established for any given frequency,

then any frequency greater or less than this predetermined frequency will cause the current to he very considerably reduced.

To give a concrete example:

capacity to be 530 microfara ds, the coefficient of self-in luction 13.3-inillihenrys, the resistance 1 ohm, the electroinotive force 5 volts, and the frequency cyc then 5 ainperes will flow throu. It now. leaving the circuit motive force th same, the changed to 25 cycles, the currc lcs per second; {:11 the circuit.

and the electrolrequr-ncy he nl'. will he only relays I this i'inu'st floW through each a cu ent of sullicient value'to produce the Suppose the.

will render the relay inoperative.

0.5 of an ampere; or if the frequency he changed to 100 cycles, the current will he only 0.9 of an ampere. It can he seen from this that either increasing or decreasing the frequency causes the current to rapidly drcrease. It is on this principle that l. depend for making the relay operative at a given frequency, and not operative at a frequency greater or less than this given frequency.

In the drawing, 1 show a relay having cores 2 and 3 of magnetic material, and which are preferably laminated.

4 and 5 are coils arrangml to cause a magnetic flux in the cores 2 and 3, whose path is indicated by dotted lines 6 and 6*. The coils are arranged in two electric circuits connected to conductors 7 and 8 through both of which currents of dill'erent frequencies are passing. In. the circuit of the coil 5 is placed a condenser E); and the capacity of this condenser is preferably so adusted in relation to the reactance of the coil 5, that at a given frequency the electroniotive force and current are in phase or i iearly so, the current in coil 5 producing a finagnetic flux in the core 3. T he current flowing incircuit through the coil 4 will lag behind the eleictro-hmtive force, and consequently his out of phase with the current flowing through the coil 5. The flux induced inthe core 2 will therefore lag behind that induced in the core 3; and if a vane or movalile element of conducting material be subected to the influence of these currents, the lag will cause a movement of such vane. I

have shown such a vane at 1-0 which is pivoted at 11, and moves -witl iii registering lot the adjacent legs of the cores. The. vane may he provided; with an arm 32 which closes contacts tit-13,thusconipleting a local circuit 14 which may contain a source 'of current and a signal or other device to he i operated.

the relay to pperate there of the two windings In order for desii d'niagnetic flux in the. cores and a dccrea'se oftlie current value in either winding The condenser or. capacity which is in series with one of the windings acts to -rcduce the value of the current .l'lowing in this winding except that current has the predetermined l'requcncy which .rill produce a state of resonance in the circuit of this winding.

"coil 5.

The relay is so designed that it will not llQ operated except by a current in the track circuit of predetermined frequency, being inoperative on e CUIi'QHt having a frequency of a. diiierent miue, such as the propulsion current of an zxlteinsting current electric milzmnl. While there may be a tendency ofthe rcley to opts-ate on a. cuirent of a differ ent frequency than that of the predetermined one, the coils of the reiey will not receive suiiicient current to operate the movable member or vane except at the predetermined frequency. Both the coils 4 and 5 are errengeli to have the same inductance, the capacity 9 being adjusted to suit the The advantages of my iiivention result from the simplicity and eliectiveness of the selective relay, and its not being lisble to be operated by unioaiencing of the propulsion current 01' by strsy currents.

The device is of special value for block signei systems and may be used on electric milroeds having either alternating current or direct current,- or on steem roads or those having other 'meens for propulsion of the cars. Many changes may be made in the form and arrangement of the soils, the means ice 453 mm? ireqsescy to cease the movesie eieeese zfint to operate, said. movable element being arranged to move in the 0p wsite direction when either one of t e "yin ings is dener gized. below a predetermined value, substantieiiy described.

2: in a frequency relay, two wind ngs having separate magnetic cores in which are produced by. the current flowing in said windings, movebie element subjecteai to the combined influence of the fluxes and ermngcd to make at partial revolution under such combined influences, soil a condenser included in the circuit of one of the windings to remit the some resoi'ient under the ini iw once of 2. current of e predeteiiztnineil frequency and to prevent the flow oi' su current of any other frequency to cause the movable element to o aerate, said movable element being arrange to move in the onposite direction when either one of the Winciugs is ileenergized below at predetermined value,

substentialiy as described.

3. A frequency relay having twowindings of substantially equal inductance arranged to produce fluxes, a movableeienient subjected to the combined influences of the fluxes, and means to render the circuitof one of the windings resonantunder the influence of it current of a predetei'mined frequency, substantially as described.

4. A frequency relay having two windings of substantially equal inductance arranged to produce fluxes, a. movable element subjected to the combined influence of the fluxes end a. condenser in the circuit of one of the windings to render the same resonant under the influence of current of at predetermined frequency, substantially as described.

in testimony whereoffli have hereunto set my heed.

DANIEL J, McCAfiiiIHY.

Witnesses:

Jess Emme it, 

